yeqirunoutlookcom • 2020-09-22 15:35:15

Processes are independent among each other. They can not communicate with each other to some extent. Five ways. PostVer 0

997371991qqcom • 2020-09-22 15:43:34

1.Because the user space of processes is independent of each other, and generally speaking, it is not accessible to each other.

2.There are 5 different ways of IPC They are pipe, message queue, semaphore, shared storage and sockets. PostVer 0

1720650158qqcom • 2020-09-22 15:44:45

Synchronization of read and write operations between processes is not possible with the operating system. It must be resolved by each process using other synchronization tools. In addition, because memory entities exist in the computer system. Therefore, it can only be Shared by the processes in the same computer system, which is not convenient for network communication.

The communication mechanism of the process mainly includes: pipeline, named pipeline, message queue, semaphore, Shared space, signal, socket.

Pipe: A half-duplex mode of communication in which data flows only in one direction and is used only between related processes. Genetic relationship of processes usually refers to the relationship between father and son processes.

Advanced piping (POPEN) : Another program is started in the current program process as a new process, then it is a child of the current program. This is called advanced piping.

Named pipe: Named pipe is also a half duplex communication mode, but it allows communication between unrelated processes.

Message queue: A message queue is a linked list of messages, stored in the kernel, and identified by a message queue identifier. Message queuing overcomes the disadvantages of little signal transmission, only unformatted byte streams and limited buffer size.

Semaphore (semaphore) : A semaphore is a counter that can be used to control access to a Shared resource by multiple processes. It is often used as a locking mechanism to prevent one process from accessing a Shared resource while another process is accessing that resource. Therefore, it is mainly used as a means of synchronization between processes and between different threads within the same process.

Signal (Sinal) : A signal is a complex form of communication used to inform the receiving process that an event has occurred.

Shared Memory: Shared memory maps a piece of memory that can be accessed by other processes. This Shared memory is created by one process but accessed by multiple processes. Shared memory is the fastest FORM of IPC, and it is specifically designed for inefficient interprocess communication. It is often used in conjunction with other communication mechanisms, such as signal two, to achieve synchronization and communication between processes.

Sockets: Sockets are also an interprocess communication mechanism. Unlike other communication mechanisms, they can be used for process communication between different machines.

Interprocess communication IPC:

IPC (InterProcess Communication) refers to the dissemination or exchange of information between different processes.

The common forms of IPC are pipes (including nameless and named pipes), message queues, semaphores, Shared stores, sockets, Streams, and so on. Where Socket and Streams support two processes IPC on different hosts. PostVer 0

kagenzaclaudiengmailcom • 2020-09-22 18:24:32

Because of the following reasons:
<ul class="b_vList b_divsec b_bullet">
<li data-priority=""><i data-bm="36"><i class="01">Information</i> sharing - Since several users may be interested in the same piece of information (for instance, a shared...</i></li>
<li data-priority=""><i data-bm="37"><i class="01">Computation</i> speedup - If we want a particular task to run faster, we must break it into <i class="01">sub-tasks</i>, each of which will be.</i></li>
<li data-priority=""><i data-bm="38"><i class="01">Modularity</i> - We can construct the system in a modular fashion, dividing the <i class="01">system</i>.</i></li>
</ul>
A process can be of two types:
<ul>
<li>Independent process.</li>
<li>Co-operating process.</li>
</ul>
An independent process is not affected by the execution of other processes while a co-operating process can be affected by other executing processes. Though one can think that those processes, which are running independently, will execute very efficiently, in reality, there are many situations when co-operative nature can be utilised for increasing computational speed, convenience and modularity. Inter process communication (IPC) is a mechanism which allows processes to communicate with each other and synchronize their actions. The communication between these processes can be seen as a method of co-operation between them. Processes can communicate with each other through both:
<ol>
<li>Shared Memory</li>
<li>Message passing</li>
</ol> PostVer 0

shatino94163com • 2020-09-23 12:13:04

Inter-process communication (IPC) requires the use of resources, such as memory, which are shared between processes or threads. If special care is not taken to correctly coordinate or synchronize access to shared resources, a number of problems can potentially arise.

a) Starvation:

A starvation condition can occur when multiple processes or threads compete for access to a shared resource. One process may monopolize the resource while others are denied access.

b) Deadlock

A deadlock condition can occur when two processes need multiple shared resources at the same time in order to continue. Example: Thread A is waiting to receive data from thread B. Thread B is waiting to receive data from thread A. The two threads are in deadlock because they are both waiting for the other and not continuing to execute.

c) Data Inconsistency:

When shared resources are modified at the same time by multiple resources, data errors or inconsistencies may occur. Sections of a program that might cause these problems are called critical sections. Failure to coordinate access to a critical section is called a race condition because success or failure depends on the ability of one process to exit the critical section before another process enters the critical section. It is often the case that two processes are seldom in the critical section at the same time; but when there is overlap in accessing the critical section, the result is a disaster.

&nbsp;
2)

Inter-process Communication<b> </b>is set of interfaces, which is usually programmed in order for the programs to communicate between series of processes. This allows running programs concurrently in an Operating System. These are the methods in IPC:

a)Pipes (Same Process) –This allows flow of data in one direction only. Analogous to simplex systems (Keyboard). Data from the output is usually buffered until input process receives it which must have a common origin.

b)Names Pipes (Different Processes) –This is a pipe with a specific name it can be used in processes that don’t have a shared common process origin. E.g. is FIFO where the details written to a pipe is first named.

c)Message Queuing<b> -</b>This allows messages to be passed between processes using either a single queue or several message queue. This is managed by system kernel these messages are coordinated using an API.

d)Semaphores<b> –</b>This is used in solving problems associated with synchronization and to avoid race condition. These are integer values which are greater than or equal to 0.

e) Shared memory<b> –</b>This allows the interchange of data through a defined area of memory. Semaphore values have to be obtained before data can get access to shared memory.

f) Sockets<b> –</b>This method is mostly used to communicate over a network between a client and a server. It allows for a standard connection which is computer and OS independent. PostVer 0

1730854984qqcom • 2020-09-23 12:22:33

Processes that execute concurrently within an operating system can be stand-alone or cooperating processes. A process is independent if it cannot influence or be influenced by other processes. Obviously, a process that does not share data with any other process is independent. On the other hand, a process in a system is cooperating if it can influence or be affected by other processes. Cooperating processes require an inter-process communication (IPC) to allow processes to exchange data and information with each other.

There are seven ways: pipe, named pipe, semaphore, message queue, signal, shared memory, socket. PostVer 0

2470994471qqcom • 2020-09-23 15:01:00

2018329621137 张翔
<ul>
<li>Interprocess communication (IPC) requires the use of resources, such as memory, which are shared between processes or threads. If special care is not taken to correctly coordinate or synchronize access to shared resources, a number of problems can potentially arise. For example, a starvation condition can occur when multiple processes or threads compete for access to a shared resource. One process may monopolise the resource while others are denied access.</li>
<li>8 ways.:pipe, popen, named pipe, message queue, semophore, sinal, shared memory, socket</li>
</ul> PostVer 0

hokyeejaufoxmailcom • 2020-09-24 09:57:55

<ol>
<li>That is because processes are <strong>independent</strong> and they cannot be affected by the execution of another process.</li>
<li>There are 8 ways in for IPC: pipe, named pipe, signal, message queue, shared memory, semaphore and socket, memory-mapped file.</li>
</ol> PostVer 0

653968106qqcom • 2020-09-24 14:46:47

&nbsp;

徐天然2018329621008

The reason why communication among the processes is not easy:

The synchronization of read and write operations between these processes cannot be realized by the operating system. It must be solved by each process using other synchronization tools. In addition, because the memory entity exists in the computer system, it can only be shared by the processes in the same computer system, which is not convenient for network communication. Different process communication methods have different advantages and disadvantages. Therefore, for different application problems, the communication mode between processes should be selected according to the situation of the problem itself.

&nbsp; PostVer 0

1285795916qqcom • 2020-09-26 11:07:25

2018329621199邱锐鹏 My answer is in the following text file. <a href="http://www.yvsou.com/wp-content/uploads/sites/30/2020/09/邱锐鹏_discussion2.txt">邱锐鹏_discussion2</a> PostVer 0

244766935qqcom • 2020-09-27 13:02:33

2018329621184-边凯昂

If in Shared-Memory Systems

Inter process communication using shared memory requires communicating processes to establish a region of shared memory. Typically, a shared-memory region resides in the address space of the process creating the shared-memory segment. Other processes that wish to communicate using this shared-memory segment must attach it to their address space. Recall that, normally, the operating system tries to prevent one process from accessing another process’s memory. Shared memory requires that two or more processes agree to remove this restriction. They can then exchange information by reading and writing data in the shared areas. The form of the data and the location are determined by these processes and are not under the operating system’s control. The processes are also responsible for ensuring that they are not writing to the same location simultaneously.

in Message-Passing Systems

The scheme requires that these processes share a region of memory and that the code for accessing and manipulating the shared memory be written explicitly by the application programmer. Another way to achieve the same effect is for the operating system to provide the means for cooperating processes to communicate with each other via a message-passing

facility.

&nbsp;

There are two fundamental models of inter-process communication: shared memory and message passing PostVer 0

yeqirunoutlookcom • 2020-09-28 15:48:39

Because they have independent data and memory.

pipe, queue, semaphore, share storage ,  sockets and so on. PostVer 0

1403861656qqcom • 2020-09-28 17:00:27

1.

1) pipe

Disadvantages of nameless pipeline: 1) it is limited to one-way communication; 2) it can only be created between its processes and those of which it is related; 3) Limited buffer zone;

Disadvantages of named pipelines: 1) It is stored in the system for a long time and easy to make mistakes due to improper use; 2) Limited buffer

2) Disadvantages of semaphore: Limited semaphore

3) Disadvantages of message queue: Information replication requires extra CPU time and is not suitable for situations with large amount of information or frequent operations

4) Disadvantages of Shared memory: 1) Communication is realized by directly attaching the co-unrealizable Shared space buffer to the virtual address space of the process, so the synchronization problem of read and write operation between processes; 2) Use memory buffer to exchange information directly. The entity of memory exists in the computer and can only be Shared by many processes in the same computer system, which is not convenient for network communication

5) Socket: it can be used for different and inter-process communication. Disadvantages: 1) The transmitted data needs to be analyzed and converted into application-level data

2.Pipes, message queues, semaphores, Shared memory, sockets PostVer 0

512858048qqcom • 2020-09-28 21:10:02

<ol>
<li>Why  communication among the processes is not easy?</li>
</ol>
Because each process has a different user address space, and the global variables of any process cannot be seen in another process, so data exchange between processes must pass through the kernel .Data storage between different processes is isolated from each other, each process can only access the data it owns.

2. How many ways are there for the inter-process communication?

seven ways.
<ol>
<li>Pipe : The essence of the pipeline is a kernel buffer. The process accesses data from the buffer in a first-in, first-out manner. The process at one end of the pipeline writes data into the buffer sequentially, and the process at the other end reads data sequentially.</li>
<li>Named pipe(FIFO): A named pipe is different from an anonymous pipe in that it provides a path name associated with it, and exists in the file system in the form of a file of a named pipe. In this way, even a process that is not related to the creation process of the named pipe can be accessed This path can communicate with each other through well-known pipes.</li>
<li>Signal: A signal is a mechanism used in the Linux system to communicate or operate between processes. The signal can be sent to a process at any time without knowing the state of the process.</li>
<li>Message queue: The message queue is a linked list of messages stored in the kernel, and each message queue is represented by a message queue identifier.</li>
<li>Share memory: This allows multiple processes to directly read and write the same memory space, which is the fastest form of IPC available. It is designed for the low efficiency of other communication mechanisms.</li>
<li>Semaphore: The semaphore is a counter used for multi-process access to shared data. The purpose of the semaphore is to synchronize between processes.</li>
<li>Socket: Socket is a communication mechanism, by virtue of this mechanism, the development of the client/server (that is, the process to be communicated) system can be carried out on a local stand-alone computer or across the network.</li>
</ol> PostVer 0

1210775967qqcom • 2020-09-28 21:22:10

Cooperating processes require an inter process communication (IPC) mechanism that will allow them to exchange data and information. However, s process is a separate unit of resource allocation. Resources between different processes (and by process I usually mean user processes) are independent, unrelated, and cannot be accessed directly from one process to another (such as open file descr iptors).
The ways for inter-process commucation.
1. Nameless pipe communication
2. Advanced pipeline communication
3. Named pipe communication
5. Semaphore communication
6. Signal
7. Shared memory communication
8. Socket communication PostVer 0

627864699qqcom • 2020-09-28 22:28:59

When one process need to communication with another process, there are may ways but all of them have challenges.When they use FIFO file to communcate with each other, they may ask for the same memory and that will cause a conflict. At the same time if we use a pipe to connect two processes, it will be a single way ticket.The buffer size will be another chanllenage.
a)Pipes(same process)
b)Name Pippe(different process)
c)Message Queuing
d)Semeaphores
e)Shared memory
f)Sockets PostVer 0

454234624qqcom • 2020-09-29 00:10:09

<ol>
<li>The user space of processes is independent of each other, generally speaking, it is not accessible to each other. The only exception is the shared memory area.</li>
<li>Eight.</li>
</ol>
<strong>Pipe: </strong>pipe is a half-duplex communication mode, data can only flow in one direction, and can only be used between processes with affinity. The kinship of a process usually refers to the parent-child relationship.

<strong>Named pipe FIFO: </strong>named pipe is also a half-duplex communication mode, but it allows communication between unrelated processes.

<strong>Message queue:</strong> message queue is a linked list of messages, stored in the kernel and identified by the message queue identifier. Message queue overcomes the disadvantages of less signal transmission information, pipeline can only carry unformatted byte stream and limited buffer size.

<strong>Shared memory:</strong> shared memory is to map a piece of memory that can be accessed by other processes. This shared memory is created by one process, but can be accessed by multiple processes. Shared memory is the fastest IPC mode. It is specially designed for the low efficiency of other inter process communication. It is often used with other communication mechanisms, such as semaphores, to achieve synchronization and communication between processes.

<strong>Semaphore:</strong> semaphore is a counter that can be used to control access to shared resources by multiple processes. It is often used as a locking mechanism to prevent other processes from accessing the shared resource when it is accessing it. Therefore, it is mainly used as a means of synchronization between processes and between different threads in the same process.

<strong>Socket:</strong> socket is also a kind of inter process communication mechanism. Different from other communication mechanisms, it can be used for different and inter process communication.

<strong>Signal (signal): </strong>signal is a more complex communication method, used to inform the receiving process that an event has occurred.

<strong>Popen:</strong> if another program is started as a new process in the current program process, it is regarded as a child process of the current program. In this way, we become the advanced pipeline mode. PostVer 0

cfeshete97gmailcom • 2020-09-30 02:40:59

Cooperation between processes requires mechanisms that allow processes to communicate data between each other and synchronize their actions so they do not harmfully interfere with each other. Interprocess communication is the mechanism provided by the operating system that allows processes to communicate with each other. This communication could involve a process letting another process know that some event has occurred or the transferring of data from one process to another.

A computer provides many resources which allow processes to communicate with each other. These resources are Interprocess Communication (IPC) Facilities. The simplest, is through the file system on disk. This is a resource that all processes in the system share, and with appropriate file permissions, two otherwise unrelated processes can exchange data. There are three problems with using files to communicate:

Processes can only communicate if they share the same file system. A network such as the internet opens-up possible connections between processes. The network socket is the IPC facility provided by the operating system to allow access for processes through a network.
Because files reside on disk, access to them is VERY slow, so using files as a means of IPC is very slow and inefficient.
Because files are so easily accessed, they make it very difficult to synchronize processes to ensure that their cooperation is not destructive. The Reader/Writer Problem frequently arises through the unintentional activities of processes sharing files.
It is because of the second and third problem that the Kernel provides alternative methods of IPC. PostVer 0

2031115154qqcom • 2020-10-01 19:51:25

Why communication among the process is not easy?

1, The memory address space owned by each process is independent of each other (except for shared memory areas), and for security reasons, one process cannot directly access the address space of another process.

2, Coordination issues. Ensure that the exchanges between processes are coordinated and orderly.

3, Data security and data integrity issues. Make sure that the data exchanged between processes is correct and complete.

4, Efficiency issues.

How many ways are there for the inter-process communication?

One category is direct communication and the other is indirect communication.

Operating system provides 3 advanced process communication methods, namely Shared-memory, Message-passing, and PIPE (Shared-document),.Shared-memory and PIPE are indirect communication. Message-passing has both direct communication and indirect communication, and direct Message-passing hangs formatted messages directly to the end of the receiving process message buffer queue, while indirect message-passing is the sending process sending formatted messages to the mailbox first, and the receiving process to the mailbox.

. PostVer 0

439731491qqcom • 2020-10-04 14:07:53

<strong>Q1:Why communication among the processes is not easy?</strong>

<strong>Ans:</strong> Each process has its own independent address space. Under the address protection mechanism of operating system and hardware, the communication among the processes is not easy, because the process cannot access the address space of other processes, the communication between processes must be realized by means of the system call function of operating system.

<strong>Q2: How many ways are there for the inter-process communication?</strong>

<strong>Ans:</strong> There are 6 ways for the inter-process communication.
<ol>
<li>pipe: A pipe is a first-in, first-out flow of information that allows multiple processes to write data to the pipe and  read data from the pipe. During read/write, the operating system ensures that the data is written in the same order.</li>
<li>message queue: A message queue is a linked list of messages, stored in the kernel and identified by a message queue identifier. Message queuing overcomes the disadvantages of little signal transmission, only unformatted byte streams and limited buffer size.</li>
<li>semophore: A semaphore is a counter that can be used to control the access of multiple processes to a shared resource. It is often used as a locking mechanism to prevent one process from accessing a shared resource while another process is accessing that resource. Therefore, it is mainly used as a means of synchronization between processes and between different threads within the same process.</li>
<li>signal: A signal is a more complex form of communication used to inform the receiving process that an event has occurred.</li>
<li>shared memory: Shared memory maps a piece of memory that can be accessed by other processes. This Shared memory is created by one process but accessed by multiple processes. Shared memory is the fastest form of IPC, and it is specifically designed for inefficient interprocess communication.</li>
<li>socket: The socket is also an interprocess communication mechanism. Unlike other communication mechanisms, it can be used for process communication between different machines.</li>
</ol> PostVer 0

450766287qqcom • 2020-10-18 23:17:16

A process can be of two types, Independent process and Co-operating process.
An independent process is not affected by the execution of other processes while a co-operating process can be affected by other executing processes. Though one can think that those processes, which are running independently, will execute very efficiently, in reality, there are many situations when co-operative nature can be utilised for increasing computational speed, convenience and modularity. Inter process communication (IPC) is a mechanism which allows processes to communicate with each other and synchronize their actions. The communication between these processes can be seen as a method of co-operation between them.

Two ways. Processes can communicate with each other through Shared Memory and Message passing.
PostVer 0

wx287_oz26ft1wt2_isbggtha4lgepaasa • 2020-10-27 14:34:15

The reason why communication among the processes is not easy: The synchronization of read and write operations between these processes cannot be realized by the operating system. It must be solved by each process using other synchronization tools. In addition, because the memory entity exists in the computer system, it can only be shared by the processes in the same computer system, which is not convenient for network communication. Different process communication methods have different advantages and disadvantages. Therefore, for different application problems, the communication mode between processes should be selected according to the situation of the problem itself.

&nbsp;

6 ways for the inter-process communication: 1.Pipeline 2.Semaphore 3.Signal 4.Message queuing 5.Shared memory 6.Socket PostVer 0

chipusilesgmailcom • 2020-11-17 14:07:34

A process can be of two types:

&nbsp;

Independent process.

Co-operating process.

An independent process is not affected by the execution of other processes while a co-operating process can be affected by other executing processes. Though one can think that those processes, which are running independently, will execute very efficiently, in reality, there are many situations when co-operative nature can be utilised for increasing computational speed, convenience and modularity. Inter process communication (IPC) is a mechanism which allows processes to communicate with each other and synchronize their actions. The communication between these processes can be seen as a method of co-operation between them. Processes can communicate with each other through both:

Shared Memory

Message passing

&nbsp;

&nbsp;

An operating system can implement both method of communication. First, we will discuss the shared memory methods of communication and then message passing. Communication between processes using shared memory requires processes to share some variable and it completely depends on how programmer will implement it. One way of communication using shared memory can be imagined like this: Suppose process1 and process2 are executing simultaneously and they share some resources or use some information from another process. Process1 generate information about certain computations or resources being used and keeps it as a record in shared memory. When process2 needs to use the shared information, it will check in the record stored in shared memory and take note of the information generated by process1 and act accordingly. Processes can use shared memory for extracting information as a record from another process as well as for delivering any specific information to other processes.

Let’s discuss an example of communication between processes using shared memory method.

&nbsp; PostVer 0

shatino94163com • 2020-12-22 14:40:18

Cooperating processes require an inter process communication (IPC) mechanism that will allow them to exchange data and information. However, s process is a separate unit of resource allocation. Resources between different processes (and by process I usually mean user processes) are independent, unrelated, and cannot be accessed directly from one process to another (such as open file descr iptors). The ways for inter-process commucation. 1. Nameless pipe communication 2. Advanced pipeline communication 3. Named pipe communication 5. Semaphore communication 6. Signal 7. Shared memory communication 8. Socket communication PostVer 0

1224532347qqcom • 2021-01-01 14:57:06

1、 Why do processes need to communicate?

1) . data transmission

One process needs to send its data to another process;

2) . resource sharing

Multiple processes share the same resources;

3) . notification events

A process needs to send a message to another process or a group of processes to inform them of some event;

4) . process control

Some processes want to completely control the execution of another process (such as debug process). The control process wants to be able to intercept all operations of another process and know its state change in time.

Based on the above reasons, there is the concept of interprocess communication. What is the principle of interprocess communication? What are the current mechanisms of interprocess communication? How do they implement interprocess communication? In this article, I will explain these problems in detail. PostVer 0

804824950qqcom • 2021-01-04 20:14:33

Inter-process communication refers to the propagation or exchange of information between different processes. The user address space of each process is independent and generally cannot access each other, but the kernel space is shared by each process, so communication between processes must pass through the kernel. The inter-process communication mechanisms provided by the Linux kernel mainly include: pipes (including unnamed pipes and named pipes), message queues, semaphores, shared storage, and Sockets. PostVer 0

2736689890qqcom • 2021-01-06 19:56:34

2018329621239-严宇豪
1.Pipeline 2.Semaphore(信号) 3.Signal 4.Message queuing 5.Shared memory 6.Socket
Data security and data integrity. different application should maintain independent. coordination issue different process have different mission there are source conflict at some time. efficiency. different process communication will cause more communication cost. if a process focus on his mission it will be efficient. PostVer 0

2736689890qqcom • 2021-01-06 19:56:39

2018329621239-严宇豪
1.Pipeline 2.Semaphore(信号) 3.Signal 4.Message queuing 5.Shared memory 6.Socket
Data security and data integrity. different application should maintain independent. coordination issue different process have different mission there are source conflict at some time. efficiency. different process communication will cause more communication cost. if a process focus on his mission it will be efficient. PostVer 0